ASP.NET Ajax Error: Sys.WebForms.PageRequestManagerParserErrorException

Question

My website has been giving me intermittent errors when trying to perform any Ajax activities. The message I get is

Sys.WebForms.PageRequestManagerP         


        

Answer 1

I also got this error. The solution reported by "user1097991" solved it for a while (I was using not-serialized objects on viewstate)

But later the error returned again, now in a random fashion. After some search I got the answer: the viewstate was becoming too large and was been truncated. I disable some viewstates on grids and menus and the problem haven't shown again.